Mizuto and Yume used to date, but now they've suddenly become stepsiblings. Both of them agree that they don't want to do anything that'd disappoint their newly remarried parents. However, neither of them can accept the other as being the eldest sibling in the relationship. So they both agree to settle the matter with a game. Whoever does something in conflict with what people might consider normal sibling behavior, loses. Making them the younger sibling.
...is kind of out of the question now.
.لم يعُد خيارًا الآن
… als hätten wir nichts
miteinander zu tun.
Se fue al diablo.
Se ha ido al garete.
… d’agir
comme de parfaits étrangers.
... ormai sia fuori questione.
...seria algo fora de questão agora.
Теперь уже не получится.